Table 4.

Summary of Studies comparing the cost-effectiveness of implant overdentures and other removable prosthetic options, in terms of cost and health outcome

Study (years)	Setting, currency, follow-up period (months)	Study design, health outcome	Study description	Outcome reported, percentage dropout
Heydecke et al. (2005)[18]	Canada, Canadian dollar; base year 1999, 12	RCT, OHIP-20	IOD group: Each subject (n=30) received a mandibular overdenture retained by ball attachments on 2 implants (ITI 048.242/243, Straumann, Waldenburg, Switzerland) opposed by a conventional maxillary CD CD group: Each subject received (n=30) maxillary and mandibular conventional CDs	Cost-effectiveness, 20% dropout
Zitzmann et al. (2006)[19]	Switzerland, Swiss Francs (CHF 100=US $61; base year 2000), 36	CCT, QAPY	Group 1: (n=20) Each subject received an implant-retained mandibular overdenture prosthesis on 2 implants and ball abutments Group 2: (n=20) Each subject received a bar-retained overdenture on 4 interforaminal implants (implant supported) Group 3: (n=20) Each subject received a conventional mandibular CD	Cost-effectiveness, 1.67% dropout
Della Vecchia et al. (2018)[20]	Brazil, Brazilian currency (1 PPP US$=1748 BRL) base year 2014, 6	RCT, OHIP-EDENT	Group 1: Each participant received 4 mini-implants (2.0 ×10.0 mm; MDL, Intra-Lock International) for overdenture Group 2: Each participant received 2 mini-implants (2.0 ×10.0 mm; MDL, Intra-Lock International) for overdenture Group 3: Each participant received 2 standard implants (4.0 ×10.0 mm; Morse Lock Straight, Intra- Lock International) + ball abutments for overdenture	Cost-effectiveness, patient satisfaction, 6.67% dropout

OHIP: Oral health impact profile, QAPY: Quality-adjusted prosthesis years, RCT: Randomized controlled trial, CCT: Controlled clinical trial, MDL: Mini Drive-Lock, IOD: Implant overdenture, CDs: Complete dentures